—— What are you doing? —— I a letter to my pen pal.A. writeB. am writing C. writesD. am w

问题补充：

—— What are you doing? —— I a letter to my pen pal.

A. write

B. am writing

C. writes

D. am write

答案：

A. write

(答案→)B. am writing

C. writes

D. am write

解析：此题考查现在进行时态。根据问句的意思你正在干什么，可知答语也应用现在进行时态，所以选B。